Bump sketches-ddsketch from 0.2.1 to 0.2.2

Bumps [sketches-ddsketch](https://github.com/mheffner/rust-sketches-ddsketch) from 0.2.1 to 0.2.2.
- [Release notes](https://github.com/mheffner/rust-sketches-ddsketch/releases)
- [Commits](mheffner/rust-sketches-ddsketch@v0.2.1...v0.2.2)

---
updated-dependencies:
- dependency-name: sketches-ddsketch
  dependency-type: direct:production
  update-type: version-update:semver-patch
...

Signed-off-by: dependabot[bot] <[email protected]>